1. Field of the Invention
The present invention relates to a satellite information operation method, and more particularly to a satellite information operation method of a global positioning system (GPS) device.
2. Related Art
A global position system (GPS) device utilizes a basic triangular positioning principle of satellites, that is, three-dimensional spatial coordinates of the position of the GPS device are calculated through measuring a distance between each satellite and the GPS device according to the position of each satellite. When the GPS device receives a satellite signal, a distance between the position of the GPS device and the satellite is obtained through a conversion carried out by an internal microprocessor. When the GPS device receives two satellite signals, the GPS device calculates the planar coordinate information thereof. When the GPS device receives three satellite signals, the GPS device obtains the coordinate information of the position thereof. Generally, a GPS device utilizes more than 4 satellite signals to determine the position and height thereof. When the GPS device receives 5 to 6 satellite signals continuously, more accurate positioning information can be obtained. Currently, 32 satellites are ejected and running in the space, which are distributed uniformly on six orbit planes. An inclination angle of the orbit is about 55°. The satellites have a satellite height of about 20,183 km, and a satellite cycle of 11 hours and 58 minutes. That is to say, each satellite orbits the earth twice along the same path in each day. This design enables users on the earth to view at least 4 satellites any time anywhere.
Generally, the GPS device obtains the satellite information by accumulating all the sampling points at a unit of 1 ms according to a sampling frequency of wireless signals, which, however, requires a large amount of operations. For example, the received satellite signals are converted into a series of digital data containing “0” and “1” after an analog-to-digital conversion. Then, an XOR operation is performed on the digital data, carrier frequencies, and C/A codes, and then the obtained results are accumulated, so as to obtain the satellite information. In other words, as the digital data is increased, the operation time is prolonged as well.